Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates

Marwa F. Abd El-Kader 1 and Tarek M. Mousa-Balabel

doi:10.5455/ajvs.265631

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Original Article
Online Published: 18 Jul 2017

AJVS. 2017; 53(2): 107-113

doi: 10.5455/ajvs.265631

Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates

Marwa F. Abd El-kader 1 And Tarek M. Mousa-balabel.

Abstract
In the last years, there were some bacterial outbreaks occurred during the summer season of farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates resulting in high fish mortalities and severe economic losses in these farms. So, this study aimed to detect the causes of the summer fish mortalities in these governorates to facilitate the diagnosis methods of study pathogens. Thirty fish farms were surveyed (20 in Kafr El-Sheikh and 10 in Dakahlia). 150 examined diseased fish (five from each farm) were succumbed for bacteriological isolation and biochemical and molecular identification. LD50 experiments were done to detect the infectivity and pathogenicity of some strains of bacterial isolates. The obtained results cleared that O. niloticus summer mortalities were caused by mixed infections with different bacterial species. The isolated bacterial species were 9 types of bacteria; 7 gram negative bacteria; 78 (30.5%) Aeromonas hydrophila, 52 (20.3%) Pseudomonas aeruginosa, 40 (15.6%) Vibrio anguillarum, 20 (7.8%) Edwardsiella tarda, 12 (4.7%) Edwardsiella ictulari, 10 (3.9%) Pseudomonas fluorescens, 7 (2.7%) Flavobacterium columnare and 2 gram positive bacteria; 30 (11.7%) Streptococcus agalactia and 7 (2.8) Enterococcus feacalis which were the most prevalent bacteria affecting fish farms and implicated in the O. niloticus seasonal summer mortalities and LD50 experiments confirmed the pathogenicity of some isolated bacteria. From the obtained results, it could be concluded that, the main cause of summer fish mortalities in studied farms was 81.82% gram negative bacteria and 18.18% was gram positive bacteria.

Key words: Infectivity, LD50, Oreochromis niloticus, summer mortalities.

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Pubmed Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel. Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates . AJVS. 2017; 53(2): 107-113. doi:10.5455/ajvs.265631

Web Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel. Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates . https://www.alexjvs.com/?mno=272886 [Access: May 06, 2025]. doi:10.5455/ajvs.265631

AMA (American Medical Association) Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel. Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates . AJVS. 2017; 53(2): 107-113. doi:10.5455/ajvs.265631

Vancouver/ICMJE Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel. Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates . AJVS. (2017), [cited May 06, 2025]; 53(2): 107-113. doi:10.5455/ajvs.265631

Harvard Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel (2017) Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates . AJVS, 53 (2), 107-113. doi:10.5455/ajvs.265631

Turabian Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel. 2017. Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates . Alexandria Journal of Veterinary Sciences, 53 (2), 107-113. doi:10.5455/ajvs.265631

Chicago Style

Marwa F. Abd El-Kader and Tarek M. Mousa-Balabel. "Isolation and Molecular Characterization of Some Bacteria Implicated in the Seasonal Summer Mortalities of Farm-raised Oreochromis niloticus at Kafr El-Sheikh and Dakahlia Governorates ." Alexandria Journal of Veterinary Sciences 53 (2017), 107-113. doi:10.5455/ajvs.265631

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APA (American Psychological Association) Style

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